Overbased oil-soluble metal salts



United States Patent 3,544,463 OVERBASED OIL-SOLUBLE METAL SALTS Emil Koft, Jr., Woodbury Heights, NJ., assignor to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Dec. 19, 1968, Ser. No. 785,394 Int. Cl. Cm 1/46, 1/40, N24 US. Cl. 252-40.7 7 Claims ABSTRACT OF THE DISCLOSURE Overbased oil-soluble metal salts are prepared by reacting a mixture comprising an oil-soluble organic acid, an alcohol and a diluent with sequential addition, under intermediate refluxing, of a metal oxide and carbon dioxide under anhydrous conditions and in the presence of a halide. Liquid hydrocarbon fuels and lubricants containing the above described salts are also provided.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to overbased oil-soluble metal salts and their use as neutralizing agents and dispersants in liquid hydrocarbon fuels and lubricants. In One of its aspects, the invention relates to the preparation of overbased oil-soluble metal salts which possess increased proportions of the oil-dispersible metal. More particularly, in this aspect, the invention relates to the preparation of overbased oil-soluble metal salts possessing increased proportions of the oil-dispersible metal over that of the normal salt, to the extent that such salts are sufficiently basic as to eflect complete neutralization and dispersancy of liquid hydrocarbon fuels and lubricants, such as motor fuels, heating oils, lubricating oils and greases.

Description of the prior art Oil-soluble metal salts have found utility as additives in liquid hydrocarbon fuels and lubricants for neutralizing the corrosive effects of acidic products encountered in fuels employed in modern internal combustion engines, for example, gasoline and diesel engines, or in lubricating oils and grease compositions in which such oils are employed as lubricating vehicles. With respect to the use of the aforementioned salts, it has been found, however, that the normal oil-soluble metal salt possesses insufficient basicity to obtain the desired neutralizing effect in the aforementioned liquid hydrocarbon fuels and lubricants, either in the course of consumption or extended use. It has also been found, in this respect, that if increased amounts of the oil-dispersible metal can be incorporated in the liquid hydrocarbon fuel or lubricant, a more eifective acid-neutralizing effect is obtained. For this purpose, the use of overbased metal salts has been suggested, i.e., salts in which the ratio of dispersed and/or combined metal equivalents to the acid equivalents (e.g., overbased calcium sulfonate) is greater than that present in the normal salt (e.g., normal calcium sulfonate). Expressed in another manner, the equivalent ratio of the metal moiety to the acid moiety is greater than 1:1. Obviously, the ability to produce a highly overbased oil-soluble metal salt as a neutralizing agent for the aforementioned organic compositions, is most desirable from a standpoint of cost and ease of treatment.

SUMMARY OF THE INVENTION In accordance with the present invention, highly overbased oil-soluble salts are prepared, as more fully hereinafter discussed by reacting a mixture comprising an oilsoluble organic acid, an alcohol and a diluent with sequential addition, under intermediate refluxing, of a metal 3,544,463 Patented Dec. 1, 1970 oxide and carbon dioxide, in which the reaction is conducted under anhydrous conditions and in the presence of a halide. These overbased salts have a metal content ratio of at least 1.5 and, preferably, as high as about 15 to 20 or higher, and a total base number (TBN), as hereinafter defined, from about 50 to about 500. More particularly, as hereinafter described, step-wise addition of the metal oxide and carbon dioxide, with intermediate refluxing, to a solution of a mixture of the organic acid and alcohol, in the presence of a diluent, is carried out, in which the mixture comprises one equivalent of the acid, at least about 0.1 equivalent of the alcohol, and wherein the metal oxide is present in an amount of at least 1.5 equivalents, and wherein carbon dioxide is present in a ratio from about 0.1:1 to about 1:1 per equivalent of the metal oxide. The overbasing is conducted under anhydrous conditions, as previously indicated, and in the presence of a halide, capable of releasing a halogen ion, which is added prior to carbonation, in any desired amount, in order to permit incorporation of the carbon dioxide. In this respect, the halide is employed in any desired amount and, preferably, in an amount from about 0.2% to about 5%, by weight of the amount of metal oxide present. As hereinafter described, an important feature of the present invention in carrying out the overbasing reaction, resides in conducting this treatment under intermediate refluxing of the metal oxide and carbon dioxide and in conducting the reaction under anhydrous conditions.

The organic acid employed in the preparation of the novel overbased salts of the present invention may comprise any oil-soluble organic acid or mixtures of such acids, and particularly preferred are sulfonic acids such as oil-soluble petroleum sulfonic acids, including mahogany sulfonic acids, alkylated aromatic sulfonic acids, paraffin wax sulfonic acids, mono-wax (eicosane)-substituted naphthalene sulfonic acid, petroleum naphthene sulfonic acids, polyisobutylene sulfonic acids, monoand poly-wax or other alkyl substituted benzene sulfonic acids, monoand poly-wax or other alkyl substituted naphthalene sulfonic acids, monoand poly-wax or other substituted cyclohexyl sulfonic acids, and their mixtures, dodecylbenzene sulfonic acids, didodecylbenzene sulfonic acids, dinonylbenzene sulfonic acid, octadecyl-diphenyl ether sulfonic acid, octadecyl-diphenyl amine sulfonic acid, ethyl-chlorobenzene sulfonic acid, bis-cetylphenyl disulfide sulfonic acid, cetoxy-caprylbenzene sulfonic acid, diluaryl-beta-naphthalene sulfonic acid, nitronaphthalene sulfonic acid, bright stock sulfonic acids, cetylcyclopentane sulfonic acid, polyethylene sulfonic acid, alkylphenol sulfides such as dodecyl phenol sufide 0r nonyl phenol sulfide, and phosphorus-containing acids, in cluding phosphonic, thiophosphoric, and phosphoric acids.

Carboxylic acids may also be employed as the oilsoluble organic acid and may include aliphatic or aromatic acids. Exemplary of such acids are palmitic acid, stearic acid, myristic acid, oleic acid, linoleic acid, behenic acid, hexatriacontanoic acid, tetrapropylene-substituted glutaric acids, polyisobutene-substituted succinic acids, such as polybutenylsuccinic anhydride, polypropylene-substituted succinic acids, octadecyl-substituted adipic acids, chlorostearic acid, 9-methylstearic acid, dichlorostearic acid, stearylbenzoic acid, poly-Wax(eicosane)-substituted naphthoic acids, dilauryl-decahydronaphthylene carboxylic acid, didodecyltetralin carboxylic acid, dioctyl-cyclohexanecarboxylic acid, and the anhydrides of such acids. It will also be understood that mixtures of the aforementioned acids in any desired proportion may also be employed for use in producing the overbased metal salts of the present invention.

The alcohol employed in the preparation of the novel overbased salts of the present invention may comprise any alcohol having as much as 30 carbon atoms per molecule. In general, the lower alkanols are preferred, viz, C to'C alkanols, of which methanol is most preferable. Moreover, these alcohols may be monohydric or polyhydric. They may also include lower alkoxyethanols, such as Z-methoxyethanol, 2-ethoxyethanol, Z-propoxyethanol, 2-butoxyethanol, and tetrahydro furfuryl alcohol. Other specific example of alcohols that can be employed, include ethanol, isopropanol, cyclohexanol, decanol, d'odecanol, behenyl alcohol, glycols, including ethylene glycol, diethylene glycol and triethylene glycol, the mono-methylether of ethylene glycol, trimethylene glycol, glycerol, pentaerythritol, benzyl alcohol, sorbitol, phenylethyl alcohol, nitropropanol, chloroethanol, aminoethanol, cinnamyl alcohol, and allyl alcohol.

The diluent employed in the preparation of the overbased salts is preferably a volatile hydrocarbon diluent and may include liquid aromatic and saturated aliphatic hydrocarbons, for example, toluene, xylene, and heptane, generally having boiling points between about 170 and 300 F. These diluents may, therefore, also include such materials as benzene, halogenated aromatic hydrocarbons, such as chlorobenzene or other materials which are normally inert to the reactants. In some instances a process oil diluent, viz, a 100" at 100 F. refined pale paraflin oil may be employed in conjunction with the aforementioned volatile hydrocarbon diluent. Other process oils which may be used as a diluent include a wide variety of mineral oils, such as naphthenic or paraffinic oils; alkylene polymers, such as polypropylene; and ester oils of polycarboxylic acids and phosphorus acids. In general, the volatile liquid inert diluent facilitates the interaction of the reactants as well as the filtration of the crude overbased metal salt-oil concentrate. In may be employed in any suitable amount, and such amount is, of necessity, based upon the composition of the initial reaction mixture. Amounts varying between about and about 40 weight percent have been found satisfactory.

The metal oxide employed for producing the overbased metal salts may comprise an alkaline earth metal base and may include the oxide of calcium, magnesium, barium,

and strontium. Calcium oxide is generally preferred. There may also be present in minor amounts of the hydroxides of the aforementioned metals as well as bicarbamates, sulfides, hydrides, formates, mercaptides, alcoholates, and phenates of the aforementioned metals. In this respect, it is found that the use of the hydroxides alone of the aforementioned metals results in the production of products which are unsatisfactory with respect to clarity and filterability. The metal oxide is employed in its anhydrous form.

As previously indicated, the preferred form of the oxide is calcium oxide. Calcium oxide, having a mesh size of from 30 to 325, and preferably 90 to 325, is most desirable. Most preferred is the use of calcium oxide having minimum mesh size of about 90. The calcium oxide employed in the following examples was of technical grade and contained about 97.5% calcium oxide.

In order to permit incorporation of the carbon dioxide into the aforementioned mixture of the organic acid reactant, the alcohol and the metal oxide, this overbasing reaction is conducted in the presence of a halide, as preferably indicated, which is capable of releasing a halide ion. For this purpose a wide variety of inorganic and organic compounds may be employed. Thus, such materials as metal halides, may be employed, e.g., zinc chloride, stannous chloride, cobalt halides, sodium chloride, sodium bromide, sodium iodide, potassium iodide, calcium chloride, barium chloride, and calcium bromide. Other halides suitable for this purpose include amine hydrocarbon halides, sulfur halides, ammonium halides, chloranil, guanidine hydrochloride, chloral hydrate and sulfonylchlorides. Particularly preferred are the inorganic halides.

In a preferred embodiment, the overbasing reaction is carried out by first forming a mixture of the oil-soluble organic acid, alcohol, metal oxide, diluent and halide. Through this mixture, maintained at a temperature below the boiling point of the alcohol, e.g., from about 50 C. to about C., and preferably from about 50 C. to about 55 C., is passed carbon dioxide gas to the extent where inlet and outlet rates are equal. At this point the introduction of carbon dioxide gas in discontinued and the reaction mixture is heated to reflux temperature, e.g., from about 60 C. to about 70 C., and is maintained at this temperature until the desired extent of refluxing has taken place. The temperature of the reaction mixture is then lowered, e.g., to about 50 C., and additional metal oxide is added. The addition of the metal oxide is then followed by further carbonation employing additional carbon dioxide gas. More diluent is added, if necessary, and the temperature of the reaction mixture is raised sufficiently high to effect removal of the volatile components by distillation, e.g., 150 C. Vacuum is then applied and the reaction mixture is held under reduced pressure at this temperature for a desired period of time. Vacuum is then released to the atmosphere and the resulting product is then separated, e.g., by filtration, to yield a highly overbased metal salt material having a relatively high total base number (TBN) DESCRIPTION OF SPECIFIC EMBODIMENTS The following data and examples will serve to illustrate the preparation of the novel overbased metal salts of the present invention and their specific utility with respect to their use as neutralizing agents and dispersants in liquid hydrocarbon fuels and lubricants. It will be understood, however, that it is not intended the invention be limited to the particular overbased metal salts described, their method of preparation or their use as fuels and lubricants. Various modifications and compositions, as previously indicated, can be employed and will be readily apparent to those skilled in the art.

Example 1 A mixture of 150 grams (0.196 equivalents of crackedwax benzene sulfonic acid, 40 grams (0.102 equivalents) of dodecyl phenol sulfide (prepared by the reaction of dodecyl phenol with sulfur dichloride in a mole ratio of 6:5) as a solution in chlorobenzene (75% active), 150 cc. methanol (3.71 equivalents), 550 cc. chlorobenzene (5.4 equivalents), 70 grams calcium oxide (2.4 equivalents), 4 grams calcium formate (.061 equivalents) and 2 grams of anhydrous ammonium chloride (.037 equivalents) was carbonated at the rate of 400 cc. per minute and at a temperature from about 50 C. to about 55 C. until the inlet and outlet rate were equal. Carbon dioxide gas was thus introduced to the extent where the mixture gained 52 grams. The introduced carbon dioxide gas was then discontinued and an additional 70 grams of calcium oxide (2.4 equivalents) was added. Carbon dioxide gas was again passed into the reaction mixture until no further quantity was absorbed. An additional gain of 49 grams was observed, making a total gain of 101 grams. grams of the 100 SUS at 100 F. pale parafl'in oil diluent was added and the mixture was heated to a temperature of C. to remove volatile components by distillation. Vacuum was applied (27.8" of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes at 150 C. After release of the vacuum to the atmosphere, 20 grams of a clay filter aid material was added. A semi-solid product was obtained which was incapable of being filtered.

Example 2 The same mixture, as described in Example 1, was carbonated, under the previously described conditions, to result in a carbon dioxide increase of 52 grams in the first treatment step. The introduction of carbon dioxide gas was then discontinued and the reaction mixture was then heated to reflux temperature (60-68 C.) and held at this temperature for a period of 30 minutes. The temperature was then lowered to 50 C. and a second charge of calcium oxide (70 grams) was added. This addition was followed by carbonation with a further quantity of carbon dioxide gas and resulted in a carbon dioxide gain of 45 grams, making a total gain of 97 grams. 135 grams of the aforementioned diluent oil of Example 1 was added and the mixture was heated to a temperature of 150 C. to remove volatile components by distillation. Vacuum was applied (27.8" of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes at 150 C. After release of the vacuum to the atmosphere, 20 grams of a clay filter aid material was added. The resulting product, after filtration, was obtained in an amount of 442 grams of a bright material, having the following analysis:

Calciuml 6.6 (TBN )449 Carbon dioxide15.8%

The reference to the total base number of the salt (TBN) in the foregoing and subsequent examples indicates the amount of calcium available for neutralizing acids. This value is found by titrating the product with perchloric acid, the base number being reported in terms of milligrams of KOH per gram of sample.

Example 3 A mixture of 145 grams (0.19 equivalents) of a cracked-wax benzene sulfonic acid, 40 grams (0.102 equivalent) of dodecyl phenol sulfide (prepared by the reaction of dodecyl phenol with sulfur dichloride in a mole ratio of 6:5) as a solution in chlorobenzene (75% active), 125 cc. methanol (3.09 equivalents), 500 cc. chlorobenzene (4.9 equivalents), 85 grams calcium oxide (2.91 equivalents), 2.5 grams calcium formate (.038 equivalent) and 1.3 grams of anhydrous zinc chloride (.019 equivalent), was carbonated at a temperature from about 50 C. to about 55 C. until no further absorption was observed. The introduction of carbon dioxide gas was then discontinued and the clear reaction mixture was then heated to reflux temperature and held at that temperature (60-69 C.) for a period of one half hour. The reaction mixture was then cooled down to 50 C. and 75 grams (2.67 equivalents) of calcium oxide were added. Carbon dioxide gas was again passed into the reaction mixture until no further quantity was absorbed. A gain of 98 grams was observed. An oil blend of 125 grams of the paraflin oil diluent of Example 1 and 17 grams of polybutenyl succinic anhydride (900 molecular weight, as a 75% solution in chlorobenzene) was added and the resulting mixture was heated to a temperature of 130 C. to remove volatile components by distillation. Clay filter aid material was then added and the chlorobenzene solution was filtered. The solvent was removed from the filtrate by distillation at a temperature of 150 C. Vacuum was applied (28" of Hg) and the reaction mixture was held under reduction pressure for a period of 30 minutes at 15 C. After release of the vacuum to the atmosphere, the resulting product was obtained in an amount of 431 grams of a bright material, having the following analysis:

Calcium-4 6.7 (TBN) 445 Carbon dioxidel 6.5

Example 4 The same procedure utilizing the same reactants employed in Example 3 was repeated except that 2.2 grams of stannous chloride instead of 1.3 grams of zinc chloride was employed. The total uptake of carbon dioxide was 102 grams (4.64 equivalents). The resulting product,

after filtration, was obtained in an amount of 421 grams of a brightmaterial, having the following analysis:

Calcium16.9 (TBN)-482 Carbon dioxide-47.0%

Example 5 A mixture of 230 grams (0.301 equivalent) of a crackedwax benzene sulfonic acid, 125 cc. methanol (3.09 equivalents), 500 cc. chlorobenzene (4.9 equivalents), 75 grams calcium oxide (2.67 equivalents), and 4 grams of stannous chloride was carbonated at a temperature from about 50 C. until no further carbon dioxide gas was absorbed. The introduction of carbon dioxide gas was then discontinued and the reaction mixture was then heated to reflux temperature (60-70 C.) and held at this temperature for a period of 30 minutes. The temperature was then lowered to 50 C. and a second charge of 70 grams (2.5 equivalents) of calcium oxide was added. This addition was followed by carbonation with a further quantity of carbon dioxide gas and resulted in a total carbon dioxide gain of grams. 140 grams of the diluent oil of Example 1 was added and the mixture was heated to a temperature of 150 C. to remove volatile components by distillation. Vacuum was applied (27.5 of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes. After release of the vacuum to the atmosphere, 20 grams of clay filter aid material was added. The resulting product, after filtration, was obtained in an amount of 439 grams of a bright material, having the following analysis:

Calcium-14.9 (TBN )390 Carbon dioxide-14.4%

Example 6 A mixture of 230 grams (0.301 equivalent) of cracked-wax benzene sulfonic acid, 40 grams (0.049 equivalent) of an oil solution of nonylphenol sulfide (present in an amount of 35%, by weight, in a SUS at 100 F., pale paraflin oil diluent), 200 cc. chlorobenzene (1.96 equivalents), 100 cc. methanol (2.5 equivalents), 75 grams calcium oxide (2.67 equivalents), 4 grams calcium formate (.06, equivalent), and 4 grams of guanidine hydrochloride was carbonated in accordance with the procedure of Example 2 and the reaction mixture was then heated to reflux temperature (60-70 C.) and held at this temperature for a period of 30 minutes. The temperature was then lowered to 50 C. and a second charge of 75 grams (2.67 equivalents) of calcium oxide was added. This addition was followed by carbonation with a further quantity of carbon dioxide gas and resulted in a total carbon dioxide gain of 101 grams. grams of the aforementioned paraffin diluent oil was added and the mixture was heated to a temperature of C. to remove volatile components by distillation. Vacuum was applied (27.5" of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes. After release of the vacuum to the atmosphere, 20 grams of clay filter aid material was added. The resulting product, after filtration, was obtained in an amount of 570 grams of a bright material, having the following analysis:

Calcium14.9 (TBN)401 Carbon dioxide14.4%

Example 7 The same procedure utilizing the same reactants employed in Example 6 was repeated, except that 80 grams of calcium oxide (2.85 equivalents) was employed, in place of the 75 grams of calcium oxide of Example 6, and 2 grams of chloranil was employed, instead of the 4 grams of guanidine hydrochloride of Example 6. After carbonation and refluxing had taken place, there were added 80 grams (2.85 equivalents) of additional calcium oxide, and an additional 1 gram of chloranil. This addition was followed by carbonation with a further quantity of carbon dioxide gas and resulted in a total carbon dioxide gain of 109 grams. 160 grams of the diluent oil of Example 1 was added and the mixture was heated to a temperature of 150 C. to remove volatile components by distillation. Vacuum was applied (27.5" of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes. After release of the vacuum to the atmosphere, 20 grams of clay filter aid material was added. The resulting product, after filtration, was obtained in an amount of 617 grams of a bright material, having the following analysis:

Calcium16% (TBN)--393 Carbon dioxide--14.4%

Example 8 The same procedure utilizing the same reactants employed in Example 7 was repeated, except that no calcium formate was employed and 10 grams of chloral hydrate was employed to replace the quanidine hydrochloride. The final product was obtained in an amount of 454 grams of a bright material, having the following analysis:

Calcium-10.4% (TBN)25'A Carbon dioxide-9.7%

Example 9 A mixture of 81 grams (0.094 equivalent) of polypropylene (800 molecular weight), phosphonic acid (2.7% P), 150 cc. chlorobenzene (1.45 equivalents), 60 cc. (1.47 equivalents) methanol and 6 grams (0.15 equivalent) calcium hydroxide was refluxed for a period of 30 minutes. The reaction mixture temperature was then lowered to 50 C; and 11 grams (0.38 equivalent) calcium oxide and 0.5 gram ammonium chloride were added to the mixture. The mixture was then carbonated at a temperature from about 50 C. to about 55 C. until the inlet and outlet rate were equal. The introduction of carbon dioxide gas was then discontinued and the reaction mixture was then heated to reflux temperature (64-68" C.) and held at that temperature for a period of one-half hour. The reaction mixture was then cooled to 50 C. and 12 grams (0.4 equivalent) of calcium oxide were added. Carbon dioxide gas was again passed into the reaction mixture until no further quantity was absorbed. A carbon dioxide gain of grams was observed. 85 grams of the diluent oil of Example 1 were added and the resulting mixture was heated .to a temperature of 150 C. to remove volatile components by distillation. Vacuum was applied (27.8" of Hg) and the reaction mixture was held under reduced pressure for a period of 30 minutes. After release of the vacuum to the atmosphere, 20 grams of clay filter aid material was added. The resulting product, after filtration, was obtained in an amount of 145 grams of a bright material, having the following analysis:

Calcium-7.35% (TBN)204 Carbon dioxide7 .2

Example 10 A mixture of 88.5 grams (0.306 equivalents) of a tall oil, and 500 ml. (4.9 equivalents) of chlorobenzene was stirred in a flask and then, with stirring, 125 ml. (3.09 equivalents) of methanol was added. An amount of 20.5 grams (0.89 equivalents) of calcium oxideand 1.0 gram 0.0187 equivalents) of ammonium chloride were added to the stirred flask contents. The resulting mixture was heated to 50-55 C. and carbon dioxide addition was started. The carbon dioxide addition required 45 minutes. The carbon dioxide uptake was determined as 11 grams (0.5 equiva lents) and then the mixture was refluxed at 65 C. for a period of 30 minutes.

The remaining calcium oxide, -viz. 25 grams (0.87 equivalents) and 0.2 gram (.0037 equivalents) of ammonium chloride were added to the flask contents. The mixture was heated to 50-55 C. and carbon dioxide addition was started again. The measured carbon dioxide uptake in the second carbonation was 20 grams (.907 equivalents).

Twenty grams (0.1 equivalents) of tridecanol was added to the reaction product and the flask contents were stripped to C. at atmospheric pressure, grams of the diluent oil of Example 1 was added and the flask contents were stripped to 150 C. at atmospheric pressure, and then for 30 minutes at 150 C. and 27.5" mercury vacuum.

Ten grams of Hy-flo filter aid was added to the stripped product and the resulting mass was filtered hot through a 0.5 bed of Hyflo filter aid under house vacuum. The final product was a clear, amber fluid having the following analysis:

Calciuml2.1 (TBN)-309 Carbon 'dioxide9.7

Example I I A mixture of 145 grams (0.19' equivalents) crackedwax (C -C benzene sulfonic acid, 30 grams (0.10 equivalents) nonyl phenol sulfide, cc. methanol, 500 cc. chlorobenzene,, 80 grams (2.78 equivalents) calcium oxide, 4 grams (0.06 equivalents) calcium for-mate and 2 grams (0.037 equivalents) ammonium chloride was carbonated with gaseous carbon dioxide at 50-55 C. until no further absorption was observed. Carbonation was discontinued and the clear reaction mixture was heated to reflux and held at this temperature (62-69 C.) for a half hour. The reaction was then cooled to 50 C. and an additional 75 grams (2.61 equivalents) of calcium oxide was added. Carbon dioxide gas was again introduced into the reaction mixture until no further absorption occurred. A gain of 107 grams was noted. An oil blend of 125 grams paraffin oil of Example 1 and 15 grams polybutenyl (90 mm.) succinic anhydride was added and the resultant reaction mixture was then heated to C. by distilling off the low boiling components. A clay filter aid was added and the chlorobenzene-oil solution was filtered. Chlorobenzene was removed from the filtrate by further distillation to C. under reduced pressure (28" Hg). After release of the vacuum to the atmosphere a bright viscous product was obtained (459 grams) having the following analysis:

Calciuml 7. 1 (TBN )472 Carbon dioxide-16.8%

the carbon dioxide are added in a sequential or step-wise manner, under intermediate reflux and under anhydrous conditions until .the desired amount of overbasing is achieved. The significance of observing these criteria is apparent when it is noted, as in Example 1, where the reaction is conducted without intermediate reflux, an unfilterable, semi-solid, product is obtained. This refluxing is essential in order to decompose the product produced by the reaction of the metal oxide and carbon dioxide. Omission of such refluxing causes a gelling or thickening of the resulting product, impairing its use as a neutralizaing agent in the aforementioned fuels and lubricants.

Another critical feature in the preparation of the overbased salts of the present invention resides in conducting the reaction under substantially anhydrous conditions. In

this respect, it is found that where the reaction is carried out in the presence of appreciable amounts of water, the metal oxide is converted to the corresponding hydroxide, and the presence of such hydroxide causes sedimentation or clogging, due to its insolubility, in various liquid hydrocarbon fuels, e.g., marine diesel fuels.

The presence of the halide, or material capable of releasing a halogen ion during the reaction, in conjunction with the aforementioned step-wise addition of metal oxide and carbon dioxide under intermediate refluxing is also a critical feature in the novel overbasing reaction to permit incorporation of the carbon dioxide, as previously indicated.

In general, the Overbased metal salts of the present invention, in a preferred embodiment, contemplates the use of these salts as neutralizing agents in liquid hydrocarbon fuels and lubricants. For such purpose, these salts may' be employed in any minor proportion, and particularly in concentrations ranging from about .001 to about 50%, by weight, of the total fuel or lubricant composition. More specifically, when incorporated into liquid hydrocarbon fuels, e.g., jet fuels, diesel fuels, turbine fuels, gasolines or the like, these salts are preferably employed in amounts from about .001 to about 0.1% by weight, of the total fuel composition. When incorporated in hydrocarbon grease compositions, they are preferably employed in an amount from about 0.1 to about by weight, of the total grease composition.

A field of specific applicability with respect to the use of the overbased metal salts of the present invention is in the improvement of liquid hydrocarbons boiling from about 75 F. to about 750 F. Of particular significance is the treatment of petroleum distillate fuel oils having an initial boiling point from about 75 F. to about 135 F. and an end boiling point from about 250 F. to about 750 F. It should be noted, in this respect, that the term distillate fuel oils is not intended to be restricted to straight-run distillate fractions. These distillate fuel oils can be straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well-known commercial methods, such as acid or caustic treatment, hydrogenation, solvent-refining, clay treatment, and the like.

The distillate fuel oils are characterized by their relatively low viscosity, pour point and the like. The principal property which characterizes these contemplated hydrocarbons, however, is their distillation range. As hereinbefore indicated, this range will lie between about 75 F. and about 750 F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range, falling, nevertheless, within the above-specified limits. Likewise, each fuel oil will boil substantially, continuously, throughout its distillation range.

Particularly contemplated among the fuel oils are Nos, 1, 2 and 3 fuel oils, used in heating and as Diesel fuel oils, gasoline and the jet combustion fuels, as previously indicated. The domestic fuel oils generally conform to the specifications set forth as ASTM Specification D396-48T. Specifications for Diesel fuels are defined in ASTM Specification D975-48T. Typical jet fuels are defined in Military Specification Ml1.F5624'B. In addition, as previously indicated, hydrocarbon lubricating oils of varying viscosity and pour points, falling both within and outside the indicated ranges for the aforementioned fuel oils, may also be effectively treated through the use of these salts.

The aforementioned greases, may comprise a combination of a Wide variety of lubricating vehicles and thickening or gelling agents. Thus, greases in which the aforementioned salts are particularly effective, may comprise any of the conventional hydrocarbon oils of lubricating viscosity, as the oil vehicle, and may include mineral or synthetic lubricating oils, aliphatic phosphates, esters and diesters, silicates, siloxanes and oxalkyl ethers and esters. Mineral lubricating oils, employed as the lubricating vehicle, may be of any suitable lubricating viscosity range from about 45 SSU at 100 F. to about 6,000 SSU at 100 F., and preferably, from about 50 to about 250 SSU at 210 F. These oils may have viscosity indexes varying from below 0 to about 100 or higher. Viscosity indexes from about 70 to about are preferred. The average molecular weights of these oils may range from about 250 to about 800, The lubricating oil is employed in the grease composition in an amount suflicient to constitute the balance of the total grease composition, after accounting for the desired quantity of the thickening agent, and other additive components to be inclined in the grease formulation.

As previously indicated, the oil vehicles employed in the novel grease formulations of the present invention, in which the aforementioned salts are incorporated for their neutralizing effect and also as anti-corrosion agents, may comprise mineral or synthetic oils of lubricating viscosity. When high temperature stability is not a requirement of the finished grease, mineral oils having a viscosity of at least 40 SSU at F, and particularly those falling within the range from about 60 SSU to about 6,000 SSU at 100 F. may be employed. In instances, where synthetic vehicles are employed rather than mineral oils, or in combination therewith, as the lubricating vehicle, various compounds of this type may be successfully utilized. Typical synthetic vehicles include: polypropylene, propylene, glycol, trimethylol propane esters, neopentyl and pentaerythritol esters, di(2-ethyl hexyl) sebacate, di- (Z-ethyl hexyl) adipate, di-butyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chaintype polyphenyls, siloxanes and silicones (polysiloxanes), alkyl-substituted diphenyl ethers typified by a butyl-substituted bis (p-phenoxy phenyl) ether, phenoxy phenyl ethers, etc.

The lubricating vehicles of the aforementioned improved greases of the present invention containing the above-described salts, are combined with a grease-forming quantity of a thickening agent. For this purpose, a wide variety of materials may be employed. These thickening or gelling agents may include any of the conventional metal salts or soaps, which are dispersed in the lubricating vehicle in grease-forming quantities, in such degree as to impart to the resulting grease composition, the desired consistency. Other thickening agents that may be employed in the grease formation may comprise the nonsoap thickeners, such as surface-modified clays and silicas, aryl ureas, calcium complexes and similar materials. In general, grease thickeners may be employed which do not melt and dissolve when used at the required temperature within the particular environment; however, in all other respects, any material which is normally employed for thickening or gelling hydrocarbon fluids for forming greases, can be used in preparing the aforementioned improved grease in accordance with the present invention.

Although the present invention has been described herein by means of certain specific embodiments, and illustrative examples, it is not intended that the scope thereof be limited in anyway, and is capable of various modifications and adaptations, as those skilled in the art will readily appreciate,

I claim:

1. An overbased oil-soluble metal salt prepared by the process which comprises the steps of:

(1) preparing a mixture of a liquid organic diluent of one equivalent of oil-soluble organic acid, at least about 0.1 equivalent of alcohol, at least about 1.5 equivalents of alkaline earth metal oxide, and from about 0.2% to about 5% by weight of halide based on the weight of the alkaline earth oxide, which halide is capable of releasing halogen ion during carbonation,

(2) reacting carbon dioxide under substantially anhydrous conditions with the mixture of step (1) at a temperature not higher than about the boiling point of said alcohol until the inlet and outlet rates are equal, wherein the carbon dioxide-alkaline earth metal oxide ratio is from about 0.121 to about 1:1,

(3) refluxing the reaction mixture of step (2) at a temperature maintained at about the boiling point of said alcohol,

(4) lowering the temperature of the refluxing mixture of step (3) to a temperature below the reflux temperature,

(5) adding an eflcctive amount of alkaline earth metal oxide to the mixture of step (4),

(6) reacting carbon dioxide under substantially anhydrous conditions with the mixture of step (5) at a temperature not higher than the boiling point of said alcohol until the inlet and outlet rates are equal,

(7) heating the mixture of step (6) to a temperature at least as high as the boiling point of said diluent to remove volatile ingredients,

(8) reducting pressure and heating the mixture of step (7) at a temperature maintained at least as high as the boiling point of said diluent, and

(9) releasing pressure and separating the overbased metal salt.

2. An overbased oil-soluble salt, as defined in claim .1, wherein said alcohol contains from 1 to 30 carbon atoms per molecule.

3. An overbased oil-soluble salt, as defined in claim 1, wherein said diluent comprises a halogenated aromatic hydrocarbon.

4. An overbased oil-soluble salt, as defined in claim 1, wherein said halide is selected from the group consisting of ammonium and metal halides.

5. An overbased oil-soluble salt, as defined in claim 1, wherein mixture of step (1) contains as additional components, eflective amounts of at least one member selected from the group consisting of dodecyl phenol sulfide, calcium formate, nonyl phenol sulfide, and polybutenyl succinic anhydride.

6. A liquid hydrocarbon fuel containing a minor effective proportion of an overbased oil-soluble salt as defined by claim 1.

7. A lubricant containing a minor eflective proportion of an overbased oil-soluble salt as defined by claim 1.

References Cited UNITED STATES PATENTS 2,881,206 4/1959 Kjonas et al. 252-33 3,014,866 12/1961 Fern 252-33 3,256,186 6/1966 Greenwald 252-33 3,282,835 11/1966 Assefi 252-33 3,347,790 10/1967 Meinhardt 25232.5

DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R.

* fg ggg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. ,5MA63 Dated December 1 1970 Inventor(s) Emil KOft. JI.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 35, for "In" read --It-- Column 4, line 8, for "in discontinued" read --is discontinued--.

Column 10, line 15, for "to be inclined" read --to be include Claim 1, line 2 for "reducting" read --reducing-.

mm mp smuzn I81 61971 (SEAL) Amst:

Edwanl M- wmw aulm m Amsfing m Oonniasiom of M158 

